Buoyant disk



Feb. 6, 1951 H. PFLEUMER 2,540,831

BUOYANT DISK Filed Oct. 24, 1944 2 Sheets-Sheet l INVENTOR. F- 6.6. HANS /Df-LEUA//EQ A'T TORNEY H. PFLEUMER BUOYANT DISK Feb. 6, 1951 2 Sheets-Sheet 2 Filed Oct. 24, 1944 l INVENTOR. HANS PFLEUMER BY W/ ATTORNEYS.

Patented Feb. 6, 1951 BUOYANT DISK' Hans Pfleunier, New` lirunswick,v N.J. assignor 'to Rubatex Productalnc., New York, N. Y., .a corporation of Delaware Application vctobe'r 24, 1944, Serial No. 560,154

2 Claims. (Cl. 9--8:)

My invention relates to buoyant members, and particularly to buoyant disks for use iioatingly supporting heavy cables, chains and the like.

In various types of marine operation, it is necessary to float a cable -or chai-n over -a long distance and to support the same by a series of buoyant members. Where the chain or cable is at interv-als to be wound up von and unwound from a drum, the buoyancym'embers, particularly when they are` rigid in form, are subject to severe distorting stresses.

Heretofore, in floating such cables and chains, hard disks -of closed cell-cellular rubber have been utilized, owing to the fact that such disks have -a spec-inc gravity of .125 or lower, while at .the same time, owing to the closed cellular structure, any break or m-arring of the surface Iof the disk will not result in the absorption of water thereby.

These hard rubber closed cell-cellular `disks are, however, rather `brittle and when the chain carrying-said disks is wound `upon a drum, the disks slide relative to each other 'or assume dii-ferent angular positions with 'respect to each other and the edges thereof may Well be broken.

rThus, for instance, in the-case of mine sweepers which are particularly adapted to remove or discharge magnetic `mines, vthe necessary exploding or removing apparatus is 'dragged behind the nii-ne `sweeper onI a Ichain 4of non-magnetic Inater-iai, preferably bronze; although 'stainless steel is at times used for some or all of the cha-in.

In order to float this chain, -a plurality of hard rubber closed cell cellular disks are mounted thereon. These disks generally are of the `order of live to six inches in diameter and approximately one to one Aand one-quarter inches thick and have an opening through the center through which the'chain passes. When -the chain is wound up on a drum on the mine sweeper, `there may be alconsiderable momentum involved i-n the chains drag kthrough the water andthe end of the chain may be heavily loaded.

The principal object of my invention is the provision lof means for reinforcing the peripheral annular surface of the 'buoyancy disks.

An additional Objectis the addition lof means for reinforcing the central hole within the disk.

Still another object of my invention is the provision of means for over-all reinforcement of the entire body of the disk.

Another object of my invention is the provision of an annular vhoop reinforcement, preferably of wood around the -outer vannular surface of the disk.

And a further obect -of my linvention is lthe 2 provision of internal reinforcing means within the body. or on. the .surfaces of the ldisk serving to maintain the disk 'and the reinforcing hoop in proper position.

.Another obect of .my invention is the utilization of. `a woo'dhoop for reinforcing purposes, since the wood. isof relatively low density and at the same time .is-nonmragnetic and therefore well adapted to this purpose.

.In my fapp'licationerial No. 404,997, now-abandoned, .I have showna method for 'internally 1rei-nfofrcing a hard rubberstr-ip by `means of 'wire or screen vvmaterial Vwhich serves Vto reinforce the 'sanrethroughout the interior vof its structure. Alsoy .my `'application Serial No. 446,069, now Patent-lo. 2,404,594, .issued July 24., 1946, I nhave shown fa means for reinforcing a hard rubber 'disk against compressive stresses which are 'exerted principally in an axial direction.

In my present application, the principal object is the reinforcement of a .rubber disk against diametric distortion Aand against chang and grinding stresses at .the corner edges and surfaces thereof.

Many other objects of my invention should in part 'be apparent rand where not. apparent will be pointed vrout in the following description and drawings, in which:

Figure 1 a plan view showing the face of a reinforcing buoyancy disk made in accordance with. my invention.

`Figure 2 is a eros-sectional view taken on line 2-2 of Figure l.

Figure 3 is a cross-sectional view corresponding to that .of Figure 12, but 'showing a modified form of my invention.

Figure '4 'is a plan View 'of a slightly modified form of buoyancy disk.

Figure 5 is a cross-sectional view taken on line 5 5 of Figure 4.

Figure '6 isa cross-sectional View of a drum, showingv a method .for wind-ing a buoyed chain on a drum.

Figure 7 isa cross-sectional view of a mod-ined form-of buoyancy disk.

Figure 8 is. a cross-sectional View sliowifng @the man-ner .in whicha chain 'carrying the Idisks of Figure 7 may be readily wound on a drum.

Figure :9 :is a cross-sectional `view of Va repair disk Seguiment taken :on fline 9--9 of Figure if@ showing the manner in which the same is slipped into placeon -the bushing.

Figure 1'0' is :a View of the repair disk segment of Figure `9 taken from line Al10n-"HJ fof Figure 9.

Figure ll is a cross-sectional View of a modified repair disk.

Referring now tc Figures 1 and 2, I have here shown a buoyancy disk Id having a central core II of hard closed cell cellular rubber, an outer annular hoop I2 of Wood and surface plates I3 also of Wood, and central opening I4 through which the chain may pass.

Preferably the hoop Iii consists of several spiral layers of hard wood riveted together as at I6 and the inner periphery of said hoop is practically round. The surfacing Wood circles or disks I3 consist of plywood and notches I8, preferably six in number, spaced 60 apart, are provided to ntercept the circumference with rubber.

The hard rubber closed cell cellular disk may be made in accordance with any of the processes set forth in Patents Nos. Re. 21,245 and 2,299,593.

The degree of hardness is controlled as set forth `in said patents by the proportion of sulphur which is mixed with the rubber. In one such typical process, a rubber mix containing a sufficient amount of sulphur and other ingredients is placed in an autoclave and subjected to pressure of an inert such as nitrogen, at a pressure of the order of 3600 pounds per square inch, until the rubber mix is fully permeated.

On relaxation of this external pressure, the entrapped gas at high pressure within the rubber mix causes the same to expand. The set and expansion of the rubber previous to its nal vulcanization are controlled by a partial vulcanization and cooling before the gassing pressure is removed, so that a multitude of minute noncommunicating cells are formed. The expansion of the rubber may then be about four times the volume of the original mix Without rupturng the cells.

In the chemical blow process gas generating chemicals are mixed with the rubber and similarly partial vulcanization is applied to` the rubber mix so that the gas generated by said chemicals may expand the rubber without rupturing the multiplicity of minute closed cells.

In either process full vulcaniaation takes place after the rubber has fully filled out the nal mold.

In the practice of the process for manufacturing the disks of Figures 1 and 2, the Wood hoop I2 is placed within the mold, a suitable central member is placed within the mold in order to form the opening I4; and disks I3, having central holes corresponding to the hole I4 are placed above and below the precured rubber II.

When rubber I I expands it flows into intimate contact with the hoop i2 and the wood disks I3, pushing them solidly against the heated mold surfaces (one of which may be formed by the press platen) While at the same time portions of the rubber' flow through the notches I8, thus binding the Wood disks to the wood hoop and iilling the interior space homogeneously With closed cell hard cellular rubber core II.

By this means, therefore, a buoyant disk may be formed having a superior compressive strength by reason of the members I2, I3 and II being integrated.

The buoyancy of the disk itself is not decreased in any Way since the added wooden hoop and wooden disks are buoyant themselves. Should it be necessary, however, that the over-al1 dimensions of the final disk be not greater than the over-all dimensions of an un-reinforced disk, then even in that event the relatively low volume 4 occupied by the wooden hoop and Wooden disk do not appreciably detract from buoyancy.

In a slightly modified form shown in Figure 3, I may utilize a single central disk 20 having an opening corresponding to the opening I4 through the buoyant disk. The central disk |20 has a shape like that of the ilat thin disks I3 and is also provided with a number of peripheral notches I I3 to permit the rubber material to flow therethrough during expansion and vulcanization.

The buoyant member of Figure 3 is also provided With a peripheral hoop |I2 like that of Figures 1 and 2. The disk |20 is a tight fit within the hoop IIZ. In the manufacture of this type of structure, procured rubber discs of equal dimensions and volume are placed on either side of the wood disk |20 and means are provided in the mold passing through the central opening of the combination III, |25, III in order to form the opening I4 for the chain.

When the buoyant disk is completed it consists of the hard cell cellular closed cell disk III, having the central stiffening co-re |20 and the stiffening hoop I I2. In a slightly modified form of the construction of Figures l and 2 which is shown in Figures 4 and 5, in addition to the outer rlat Wood disks 2I3, 2I3 and the hoop 2I2, all of which have exactly the form shown in Figures 1 and 2, a tube 25, preferably of plastic material, is provided as a lining for the central opening I4 in order to reinforce the corners thereof. This lining may be formed from the rubber material itself, or a plastic tube of any suitable material may be placed in the opening I4 before the complete rubber disk is expanded into final form.

In all oi the constructions shown in Figures 1-5, the peripheral edges of the disk are protected against chang or grinding by reason of their reinforcement by the wooden hoop I2, ||2 or 2I2 as the case may be. The Wooden hoop is maintained in appropriate spaced relation and the pressure thereof against the hard rubber core II, III or 2II is relieved by the disks I3, |20 or 2|3. In addition, as shown in Figures 4 and 5, the edges of the central opening I4 may be protected by a reinforcing tube 25.

While it is preferred that rubber be used as the closed cell expanded cellular material forming the principal body of the disk, any plastic material which may be expanded to a form having a multitude of minute or relatively minute non-communicating cells may be used for this purpose.

By the means herein described, therefore, the grinding, chang or breakage which may result from slipping or twisting of the disks on the chain is greatly minimized and the buoyant life of the disks is greatly increased.

The reinforcing members, as can readily be seen, resist compressive stresses, the denting of the edges and the chang of the central hole. In actual practice, when the chain carrying the disks is Wound up on a drum, the disks bear against each other and their edges slip, slide and grind against each other, producing additional chang and distorting forces.

As shown in Figure F., this type of slipping and grinding, owing to the uneven surface provided by each layer oi rolled up disk carrying chain, may be obvated by Winding a layer of canvas 40 between each layer of the disk carrying chain which is Wound upon the drum 'I I. As will readily be seen from Figure 6, the Winding of the layer of the canvas 40 around each layer presents a smooth surface for the next layer and thus to a great extent minimizes the destructive forces which may arise from the uneven surfaces on which superposed layers would otherwise be wound.

In the foregoing I have set forth my invention in connection only with preferred embodiments thereof. Variations in the construction and formation of the buoyancy disks as well as in the processes ci making the same should now be obvious.

Thus, for instance, Where a buoyancy disk is made in the form shown in Figure 4, it may be possible to maintain the internal gas pressure within the cells at an elevated pressure since disruptive expansion of the buoyancy disk owing to the iact that the internal elevated pressure is resisted by the conning effect of the disks I3, the reinforcing' tube 25 and the hoop I2.

Such elevated internal pressure may also be utilized in connection with the construction of Figures l and 2 but may result, however, in some constriction of the internal diameters of the opening I4. This latter effect may possibly be benencial rather than adverse since it will' ensure a tight t of the disk on the chain.

Such elevated internal. gas pressure within the buoyancy disk will provide an additional cushioning effect against any shocks which would tend to compress or destroy the disk. The process by which such elevated internal gas pressure may be obtained within the disks is more fully described in my applications Serial No. Li07,729 which has matured into Patent 2,395,293, and Serial No. 382,378 which has now matured into Pat. 2,422,797.

In Figures 7 and 8, I have shown a slight modication of my novel buoyant disk which will permit the cable or chain on which it is mounted to be cooled by the water in which the disks support it.

The metallic chain or cable tends to be heated by the electrical current owing therethrough. Ii the cable is insulated thermally from the surrounding sea water by closely adjacent buoyant disks, the heat generated therein by the current now will accumulate and will have a softening effect upon the inner portions of the disks which may warp them.

However', in Figures 7 and 8, I have shown a spacing means for the disks so that water may circulate between them and come into closer adjacency to the cable or chain thereby cooling the same.

In Figure 7, I have shown the inner tube extended at 5t to abut against the end of the tube in the adjacent disk and maintain a spacing equal to the length of extension 50 therebetween. The unit or Figure 7 is identical with that of Figure l so that elements 3I2, 3|3 and 3H thereof correspond to the similar elements I2, I3, II or Figure 1.

In Figure 8, I have shown the inner tube 25" extended at both sides at 50 and 50 so that disk spacing elements will be present on both sides of each disk.

The spacing obtained by element 50 or by elements 50 and 50" will necessarily increase the friction of the entire cable or chain unit in the water to an extent proportional to the width of the spacing; but this slight increase in friction is compensated for by the enhanced life of the disks.

The extensions 52 (Figure 7) or 50 and 50 (Figure 8) provide an additional advantage since the cable (indicated by dotted line 60) can now 75 be wound more readily over reel 42 (Figure 6) without putting any substantial compressive strain on the inner edges of the inner layers of disks, the thrust being absorbed by extensions 5S or 5S' and 5t. Accordingly, the bushings 2&3' or 25 should be of strong and stiff material.

When the cab-le or chain is rst assembled, the notation disks are slid over it to the proper position. However, should a disk be damaged, it is necessary to replace it without disturbing the others; otherwise, a completely new assembly operation 'sill be required.

Accordingly, the damaged disk may be cut up and removed. In Figures 9,v 10 and 11, I have shown replacement disks which may be positioned over the cable or chain (in place of the removed disk) without affecting adjacent disks.

In Figures 8 and 9, I have shown a repair disk segment. A disk is cut obliquely along plane 62 to produce two similar portions 63 and 64. A cut 65 is made from the center of edge 66 down through bushing 425 and communicating with opening dIll. rI'his cut is approximately the diameter of the cable or chain. The two halves 53 and bf2 are forced around the cable and surfaces @2 cemented together with, for instance, a self-setting cord rubber cement.

The repair disk segments 63 and 64 may be prefabricated and molded separately (rather than cutting apart a complete disk) and may have the surfaces 62 corrugated or indented to oier a good surface to hold an adhesive. The side surfacing disks i3 (of Figure l) may be retained, in cut form of course; but the' annular hoop I2 (of Figure l) may be replaced by a hard rubber skin St. The cut-out portions 65 need not necessarily be plugged up; but plugging wedges shaped to i-lt them may, of course, be provided; and such a wedge may be cemented in place on the rst disk segment (63 or 64) to be applied to the cable or chain; and may, if the disks can be spread slightly, be inserted in the cut-out 65 Vof the second segment to be applied.

In Figure 1l, I have shown a repair disk 70 which is slotted at II from the surface through bushing 525 to the open-ing 5M. After the Slot 'II is passed over the cable or chain, until the cable or chain is in the opening I4, a filler piece 'I2 is cemented in the slot Il. Disk 'IU may have the side wooden surfacing circles I3 (of Figure l) but, instead of the wooden hoop l2 (of Figure l) it will have a hard rubber skin 580.

Many other variations in the construction and process of making my disk should now be obvious to those skilled in the art. Accordingly, I prefer not to be bound by the specic disclosure herein, but only by the appended claims.

I claim:

l. A buoyant disc comprising a main body portion of expanded closed cell cellular hard rubber; a protective cylindrical covering for said body portion; and a stiffening member therefor, extending normal to the axis of said cylindrical covering and in engagement therewith; openings in said stilening member; said body portion being expanded into position against said covering and said stiITening member; a portion of said body portion passing through said open-- ings in said stifening member to anchor said stiifening member to said body portion, said protective covering and stiffening member being formed of relatively rigid buoyant material.

2. A buoyant disc comprising a main body portion of expanded closed cell cellular hard rubber; a protective cylindrical covering for said body portion; and a stiffening member therefor, extending normal to the axis of said cylindrical covering and in engagement therewith; openings in said stiffening member; said body p0rtion being expanded into position against said covering and said stiiening member; a portion of said body portion passing through said openings in said stiffening member to anchor said stiffening member to said body portion, said protective covering and stiffening member being formed of relatively rigid wood.

HANS PFLEUMER.

REFERENCES CIT ED Number The following references are of record in the 15 Number le of this patent:

Great Britain Aug. 11, 1938 

